Cannot see any object in viewport
All your objects have invalid coordinates, and are positioned at infinity.
Don't know how that happened but the bottom line is Blender can't handle it so you can't see your objects.

You will probably have to manually place your objects again one by one, as no other methods seem to be working currently.


Go to the outliner
Set it to Current Scene
Select one of the objects from the list
Go to the 3D view
Open the properties tool shelf N key
Change the values for location from invalid values to 0,0,0or anything else that suits you




Changing for the parent of several objects seems to be enough though, for all others you will have to manually place them in the scene at correct positions again